In my opinion this is....
The best Batman movie! animated or live-action. Now don't get me wrong, I love Tim Burton's "Batman" & "Batman Returns" I grew up watching those movies & I think they're hugely entertaining well made films. And of course I also like "Batman Begins" and "The Dark Knight." with the latter being a very VERY close second in terms of it being the best batman film, again this is all in my opinion and I know some of you will disagree.
I just feel that "Mask Of The Phantasm" still has a better plot, more depth (the scene where a tearful Bruce is pleading on his kness at his parents' grave to be released from his vow so he can be happy is one of my favorite scenes in any movie.), The film also has better character devolpment & more exciting action sequences then any of the live-action bat-flicks. The voice acting is top-notch and the animation is stylish and crisp. All of these elements help this film to stand head & shoulders above the pack.